Processes for the recovery of metal catalysts components from the mother liquor used in the oxidation of alkyl aromatic compounds such as meta and para-xylenes to isophthalic or terephthalic acid are described in U.S. Pat. Nos. 3,673,154, 3,840,469 and 4,490,297. In the '469 patent and the '297 patent the desired metals are precipitated as oxalate compounds. In the '154 patent the desired metal is precipitated as the carbonate compound. Both the '154 patent and the '469 patent refer to the problem of tramp and/or corrosion metals (iron, nickel and chromium) and include suggestions as to how to separate these metals from the desired metals. In '469 it is found that the tramp or corrosion metals do not precipitate simultaneously with the cobalt, while in '154, the iron and chromium are precipitated first by a pH adjustment. In the '469 patent the catalyst, cobalt acetate, is regenerated by mixing the cobalt oxalate in acetic acid with calcium ions. In the '154 patent the catalyst, cobalt acetate is regenerated by mixing the cobalt carbonate with an excess of acetic acid and heating. In the '297 patent the catalyst is regenerated by reacting the cobalt oxalate in acetic acid with acetyl bromide and/or hydrogen bromide.
It is an object of this invention to provide a process for the recovery of cobalt and manganese catalyst components from an acetic acid mother liquor, and lower the level of corrosion and/or trash metals in the catalyst and separating acetic acid from the mother liquor.